FIELD OF THE INVENTION
The invention relates to a multicolor printing method wherein a printed image on a printed material is attained with at least two passes.
In the known multicolor printing of this art it is necessary to set the register devices such that the process is allowed to proceed so that the register and other adjustments affecting the printing quality in a second pass are adjusted to insure that the second printed image is in registration and in all other respects matches the first printed image.
The matching is actually difficult and time consuming, since usually only few adjusting parameters from the first pass are saved, and therefore available for the following pass. As an example the storing and reuse of ink zone adjustments combined with job data on magnetic tape or on a diskette, may be mentioned.
In order to attain precise registration in a second or later passes, there are usually only register marks and printing control strips to watch, while deviations that are present in the printed image are not considered, which may lead to quality losses.
It is also known to inspect the entire surface of a printed material. The measuring signals from inspection devices are accordingly used only to influence the printing operation during the actual pass through the printing machine.